The present invention relates to a method for equalizing the delay characteristics of a circuit, in particular, relates to a method for adjusting the delay equalization characteristics of an equalizer having a plurality of quadratic all pass networks on a frequency axis.
A delay equalizer which has a plurality of quadratic all pass networks on a frequency axis and obtaining the desired delay characteristics from the total of said all pass networks is well known. That is to say, N number of quadratic all pass networks having the delay characteristics .tau..sub.1, .tau..sub.2, --- .tau..sub.n are arranged in the band width, and the total delay characteristics H is obtained from the sum of .tau..sub.1, .tau..sub.2, ---- and .tau..sub.n.
However, said prior art has the disadvantage that the adjustment of each all pass network is very difficult, since said adjustment had to be accomplished manually and the desired characteristics of a particular all pass network depends upon the characteristics of the other all pass networks. Therefore, the total characteristics of the delay equalizer depend upon the experience and the sixth sense of an operator, and further the resultant characteristic is not always the best one.